Tube base



Feb. Ml, 3.936. G. M RQSE9 JR 2,@3084 TUBE BASE Filed June 2;?, 1955INVENTOR GEGE M P055 Fr ATTORNEY Patented Feb. 11, 1936 UNITED STATESPATENT OFFICE TUBE BASE Delaware Application June 27, 1933, Serial No.677,777

7 Claims.

My invention relates to vacuum tubes and the like and more particularlyto bases for such tubes.

The conventional vacuum tube has a cupshaped base with a at bottom onwhich tubular contact pins are mounted in a circle near the rim toproject perpendicularly from the bottom of the base. These tubularcontact pins are connected to the electrode elements of the tube byleading-in wires threaded into and soldered to the pins. An increase inthe number of contact pins on the base decreases the spacing between thepins, increases the tendency for voltage breakdown through the base, andgreatly increases the difficulty of basing the tube, particularly thethreading of the leading-in wires into the contact pins.

Not only has the practical limit been reached in the number of contactpins which can be mounted in the conventional Way in a tube base ofconventional size, but tubes only about onehalf the conventionalsizemust be provided with bases having as many contact pins as theconventional sized tube. The usual lnumber of conventional sized contactpins cannot be mounted in the conventional way on a smaller base, yet acorresponding reduction in size of the contact pins will result in pinswhich are too weak for practical use, do not have enough contact area,

and offer very great diculties in the threading of the leading-in wiresinto the pins. There is a practical limit to the reduction in diameterof the contact pins and of the leading-in wires, as the wires must besufficiently large to carry the necessary current and also stili enoughto thread easily into the pins, which must, of course, have a boresomewhat larger than the wire.

The conventional contact pin is in effect riveted into the base byupsetting or spinning the inner end of the pin over on the inside of thebottom of the base. The inner end is thus enlarged and in effect thediameter of the pin is increased, so that more room is required forproper spacing between the pins. As it is not feasible to reduce thediameter of the pins, the space required for fastening the pins to thebase cannot be reduced, hence a base constructed in the usual way cannotas a practical matter be reduced in size and still be commerciallysatisfactory.

One object of my invention is to provide a base which can be made muchsmaller than the conventional base and yet have as many or even morerigid contacts of ample area which are spaced practically like thecontact pins of the conventional base, so that the electrical and me-(Cl. Z50-27.5)

chanical properties of the smaller base are ample to meet allrequirements.

Another object of my invention is to provide a base so constructed thatthe attachment of the leading-in wires to the contacts is much simplerand easier than soldering totubular contact pins.

A further object of my invention is to provide a base having rigid andstrong contacts which occupy less angular space on the base than the 10Contact pins commonly used yet have as great or even greater contactarea than the conventional contact pins.

Still another object of my invention is to provide an improved basecontact terminal which 15 is simple and inexpensive, and provides amplecontact area.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but the inven-20 tion itself will best be understood by reference to the followingspecication taken in connection with the accompanying drawing, in whichFigure 1 shows a vacuum tube having a base constructed in accordancewith my invention. 25

Figure 2 is an enlarged bottomv View of Figure 1.

Figure 3 is a longitudinal section of the lower end of the tube shown inFigure 1, taken along the line 3 3 of Figure 2.

Figures 4 and 5 are perspective views of con- 30 tact terminals made inaccordance with my invention.

Figure 6 is a sectional View of a modified form of base embodying myinvention.

Figure 7 is a perspective View of a base con- 35 tact for themodification shown in Figure 6.

The vacuum tube shown in Figure 1 of the drawing has an evacuated bulbIl) enclosing the usual cathode, anode, and grid or grids. The bulb I0has secured to it by cement a' cup-shaped 40 base comprising a shell IIwith a fla't bottom I2 and preferably molded from insulating material.

In the particular device shown in Figures 1, 2, and 3, the at bottom I2has a circular opening or aperture I3 at the center, so that the bottom45 I2 is in effect a washer or apertured disc. From the edge of theaperture I3 radial grooves I4 in the outer side of the bottom .I2 extendto the outer edge of the base as best shown in Figures 2 and 3. Near themiddle of each groove 50 is a hole I5 through the bottom I2 to theinterior of the base.

Contact terminals I6, in the form of blades or fins, are set edgewise inthe grooves I to be perpendicular to the bottom I 2. Each contact 55 hason its upper edge a fastening lug I 'I which extends through the hole I5in the bottom of the groove I4, and is upset or peened over at its innerend to fasten the contact fin IB rmly to the base.

To facilitate and simplify the connecting of the lead wires tol the basecontacts, I provide each contact on its inner edge with a connector,such as the connecting lug shown in Figure 4 or the slightly modifiedconnecting lug I9 shown in Figure 5. When the base is put on the tubeduring assembly these connecting lugs I8 or I9 practically adjoin thelead Wires 20 which project through the opening I3 in the base shell.The lead wires may be inserted in the connecting lugs and then welded tothe lugs, thus making a good electrical connection more easily than bysoldering. The threading of the lead Wires into tubular contact pins iseliminated, and the welding assures a good electrical contact.

As the contact iin I6 requires materially less angular space on the basethan the conventional tubular contact more of such contact ns can beaccommodated on a base of the usual size, or the size of the base can bematerially reduced and still the maximum number of contacts nowpractically possible in the usual size base can be used because of thesmall angular space required by the contact i'lns. These contacts withflat surfaces provide ample contact surface, at least as much as theconventional contact pin.

The flat contact blades or fins I6 may tov advantage be made of nickel,which is easily Worked and welded and may be made in various ways. Iprefer to punch them as double blanks and fold them. An advantage of thefolded punching is that the connecting lugs, as clearly shown in Figures4, 5, and 7, are formed of two halves which can be separated to permit alead wire to be placed between them. This construction produces acontact which is amply rigid and strong for its intended. use.Furthermore it greatly simplifies the manufacture of base contacts, asit is easier to make and fold the contact blanks than to make the usualtubular type contacts.

While I show a contact iin with lugs for securing it to the base shell,I may mold the contact fins into the base shell and secure them to theshell in any of the various ways commonly used to secure metal insertsin molded material. For example, I may provide a hole through a part ofthe contact n which is within the body of the base shell, so that duringthe molding process the shell material will flow into the hole and lockthe contact fin tov the shell.

It is obvious that the base can be indexed or put in the correct angularposition in the socket in various ways, for example, by placing thecontact iins nonsymmetrically around the shell, by using one or more nswhich differ from the others in thickness, or providing studs orprojectors on the base shell to enter corresponding slots in the socket.I prefer to index the base by providing a contact n which has anextension 2I, as shown in Figures 2 and 3, but Which is otherwise thesame as the other contact ns.

In Figure 6 I show another form of embodiment of my invention. The baseshell 30 is provided with a stepped portion 3| and radial slots 32 whichextend through the bottom of the base. A contact n 33 of the type shownin Figure 7 is inserted in each slot and secured in the base by peeningover the fastening lugs 34. Connecting lugs 35 engage the leading-inwires 20 and are preferably Welded to said leading-in Wires. For

this type of base a convenient registering or in-A dexing means is a pin36 secured to the base and fitting into a corresponding slot in thesocket when the base is in proper position. This pin 36 may be molded inthe base instead of being a separate element.

It will be seen that I have provided a base in which the maximum numberof pins which it is new feasible to use on the conventional base can bematerially increased and still have the base fully meet the electricaland mechanical requirements of a tube base. In accordance with myinvention I can materially reduce the size of vthe usual base and stillproperly accommodate as many contacts as can now be used on the base ofthe usual size. The threading of lead wires into tubular contact pinshas been eliminated, thus expediting manufacture, and the electricalconnection between the contact and the leading-in wires has beenmaterially improved. My invention also provides a novel contact iinwhich can be manufactured cheaply and easily from a single punching.

The embodiments of the invention illustrated and described herein havebeen selected for the purpose of setting forth the principles involved,but it Will be apparent that various modication may be made to meetdifferent conditions encountered in use, and I, therefore, intend tocover all modifications Within the scope of the appended claims.

What I claim as new is,-

1. A vacuum tube base comprising a disc of insulating material having acentral opening, flat contact fins mounted on said disc to extendradially from said opening along one surface of and perpendicularly tosaid disc and spaced around the periphery thereof, each of said contactns having one edge in engagement with and mechanically secured to saiddisc, and a connecting lug on its edge adjacent said opening.

2. A base for a vacuum tube comprising a disc of insulating materialhaving a central opening and channels extending radially from saidopening along one surface of said disc, flat contact iins mounted onedge in said channels and perpendicularly to the surface of said disc,each of said contact ns having on its edge in contact with said disc afastening lug secured to said disc and having on its edge adjacent saidopening a connecting lug for making an electrical connection.

3. In a vacuum tube, the combination with a bulb having lead wiresprojecting from one end, of a cup-shaped insulating base with a ilatbottom secured to said end of said bulb, the bottom of said base havinga central opening through which said lead wires extend, and havingchannels extending radially from said opening, flat Contact fins mountedon edge in said channels perpendicularly to said bottom and mechanicallysecured thereto, and connecting lugs on the inner edges ofsaid nsadjacent said opening and connected to said lead wires.

4. A vacuum tube base comprisingl an insulating cup with an annularbottom having channels spaced around its periphery, flat contact finsmounted on edge in said Channels perpendicularly to said bottom, afastening lug on one edge of each of said fins for mechanically securingsaid n to said bottom and a connecting lug on another edge of each ofsaid iins.

5. A vacuum tube base including a cup-shaped shell of insulation with aat bottom having radial channels spaced around the periphery of saidbottom, iiat contact fins mounted in said channels perpendicularly tosaidbottom, said ns having on their edges fastening lugs for securingthe same to said base and connecting lugs for securing lead Wires tosaid iins.

6. A vacuum tube base including a. cup-shaped base shell of insulatingmaterial having a flat bottom, flat Contact ns set on edge and radiallyof said bottom to project perpendicularly thereto and spaced around theperiphery thereof, said. ns having fastening lugs extending through saidbottom into the interior of the shell for securing said contact finsthereto.

7. A vacuum tube base including a base shell having a plurality ofcontacts each of said contacts comprising an oblong punched blank withextensions on its shorter edges, said blank being folded in half Withthe sho-rter edges in contact to make a flat contact fin, the extensionson said edges being in registry to form a lug for fastening said fmedgewse to said base, said blank being formed to provide a second lug onanother edge of said fin for securing a lead Wire 10 to said n.

GEORGE M. ROSE, JR.

